Project Summary: Two species of lionfish, Pterois volitans and Pterois miles, are the first non-native, invasive marine fishes to establish along the U.S Atlantic coast and Caribbean. Despite their successful invasion and persistence for over a decade along the Atlantic coast, there is relatively little known about the biology of lionfish in their native habitats and even less information in invaded habitats. Further understanding of the mechanisms that have allowed lionfish to invade different ecosystems is needed to implement effective management plans. We aim to understand lionfish biology by quantifying venomous spine mechanical properties, impacts on swimming, and applying results to biomimetic applications. Our aims align with the Walter & Lalita Janke Foundation Innovations in Sustainability Science Research Fund to determine the mechanisms of a successful invasive predator in our local marine ecosystems. Additionally, we hope to develop new biomimetic applications based off lionfish biology. The goals of this proposed research are to determine the mechanical roles of spines in locomotion and defense to better understand the proliferation of red lionfish, Pterois volitans, as an invasive species. Our overarching research questions are: 1) Do the spines break easily when predators encounter them or are they a flexible biomaterial? 2) How successful are the spines as a defense mechanism? 3) Is the spine defense system a tradeoff for decreased locomotor ability or are they beneficial in swimming performance? We hypothesize that the spines of lionfish are flexible to avoid breaking (Question 1), but have increased stiffness at the tips for efficient puncturing (Question 2). We predict that the spines will be retracted during swimming resulting in overall increased body stiffness, which is associated with faster swimming speeds (Question 3). Mechanical data paired with swimming kinematics will answer important questions relating to trade-offs between locomotion and the efficiency of the defense mechanism against predators.